Marine propulsion installations



T. HINDMARCH MARINE PROPULSION INSTALLATIONS May 15, 1962 2 Sheets-Sheet1 Filed Sept. 2. 1960 Z n /U&I27Z0l"' Clad/march) 1.

May 15, 1962 T. HINDMARCH MARINE PROPULSION INSTALLATIONS 2 Sheets-Sheet2 Filed Sept. 2. 1960 I IIHH! United States Patent "ice 3,034,584 MARINEPROPULSION INSTALLATIONS Thomas Hindmarch, Lindo Lodge, Stanley Ave.,Chesham, Buckinghamshire, England Filed Sept. 2, 1960, Ser. No. 53,743Claims priority, application Great Britain Sept. 9, 1959 3 Claims. (Cl.170-16032) This invention relates to marine propulsion installationswhich may include variable pitch propellers.

Certain known types of variable pitch propellers contain within thepropeller shaft a pull-push rod which is actuated by an hydraulic ram.In operation oil under pressure is applied to one side or the other ofthe ram as required in order to impart a fore or aft movement to therod. In the event of a failure of the oil supply the pitch of thepropeller blades cannot be varied or locked, but instead, on rotationthe blades are forced to feather as a result of the resistance of thewater and take up a position of no load. The ship cannot then bepropelled. Since the actuating mechanism is contained within thepropeller shaft which is designed for rotation, there is greatdifiiculty in obtaining access, particularly while the ship is at sea.The general object of the present invention is to provide an arrangementby which in such an emergency the blades can be moved into a full aheadposition and locked there to enable the ship to proceed to port underher own power. Another problem arises with ships which have reversinggears which depend for their operation on oil operated clutches.Circumstances of overheating from defective coolers, or other mishaps,might cause the hydraulic operated mechanisms to bind in an on or offposition. With part of the installation according to the inventioncoupled to the oil distribution piping system, by detaching the mostconvenient union, and attaching a connection, and then applying apowerful force with the machinery stationary the stuck part may possiblybe fieed without the necessity for dismantling.

The invention accordingly consists in a marine propulsion installationWithin a variable pitch propeller which incorporates an auxiliaryexternal high pressure oil or grease pump coupled through a passageextending through an outer casing to a piston or ram built into thepropeller shaft the arrangement permitting high pressure to be appliedto the piston or ram without dismantling the main machinery of theinstallation.

The invention further consists in a marine propulsion installationincluding means for the auxiliary actuation of the variable pitchpropeller mechanism, in which a pull and push rod is actuated byhydraulic pressure transmitted through a main hydraulic piston, locatedwithin a cylinder which is integral with the rotatable propeller shaftand fed with pressure oil from a pressure pump and control valve,characterised in that there is a separate high pressure ram, which whenin operation presses against the centre of the hydraulic main piston andwhich is 'located within a cylinder machined in the main propeller shaftor extension thereof, communicating with the outside of the shaft bymeans of drilled passages in the shaft, terminating in a non-returnvalve and which non-return valve is connected by means of a couplingwhen the propeller shaft is stationary to a source of pressure oil orgrease pumped by manual or assisted operation at a pressure high enoughto move the ram to force the main hydraulic piston to assume and toretain a fixed position corresponding to the ahead position of theblades.

The invention further consists in the installation as first describedabove but in which the main machinery piston and some of the maininstallation oil pressure channels are utilised in order to connect theemergency high pressure pump through to the piston or ram of the main3,034,584 Patented May 15, 1962 machinery by actual liquid contact bydisconnecting the main pressure piping or channels at a point nearest tothe afiected part and of having a non-return valve and connection tocomplete the combination, using a hydraulic fluid of higher than normalviscosity but which is miscible with the normal oil so that service maybe resumed without dismantling.

Among the advantages of this invention are:

(l) A complex hydraulic system need not be dismantled at sea.

(2) Minor stickages which would be eliminated eventually are avoided.

(3) In an emergency, the high expense of repairs, delays en route, andtowage can be prevented.

(4) Its adaptability, in that the normal ships engine room staff cancarry out repairs which hitherto required the services of a dockyard.

The problem, therefore is a serious one and the solution involves apractical and useful contribution to the art.

In one preferred form of the invention, an independent hydraulic ram issituated in a cylinder comprising a cen tral axial bore in the propellershaft forward of the main operating piston and cylinder.

The lengths of the independent ram and cylinder are chosen so that innormal operation when the independent ram is fully retracted, it doesnot protrude into the main cylinder.

The independent cylinder is fed via an axial and a radial hole drilledin the shaft from a non-return valve and pipe coupling situated at theoutside diameter of the shaft. To operate the emergency locking system,the shaft is stopped and a high pressure hand operated hydraulic pump isconnected to the pipe coupling. Operating the hand pump moves theindependent ram into contact with the main piston, which is then forcedin the direction required to turn the blades into ahead pitch. Thelength of travel of the auxiliary ram may be arranged so that thecorrect pitch is obtained automatically.

The non-return valve prevents leakage and so holds the blades in therequired pitch when the hand pump is disconnected. The seal used on theauxiliary ram is preferably one in which the pressure assists inproviding the sealing action, e.g. a cup seal, in order to eliminateleakage, but should any leakage occur, and the blades in consequencemove toward neutral pitch, the shaft can be stopped and the pressurerestored.

The blades are at rest when operated and consequently unloaded, and avery high pressure may he used for the auxiliary ram, which may betherefore quite small in diameter yet move the blades to and hold themin the ahead position as ef'ectively as the main piston in normaloperation. This enables a compact and economical assembly to beobtained.

A particular embodiment of the invention is illustrated in the drawingsin which:

FIGURE 1 is a schematic representation of a variable pitch propellerinstallation, Whilst FIGURE 2 is a longitudinal section on an enlargedscale showing the ram and piston assembly of FIGURE 1.

In FIGURE 1 an engine 6, drives optionally through a clutch 7, thepropeller shaft 4, integral with which a cylinder 2, contains ahydraulic main piston 1, attached to the pull and push operating rod 3,within the hollow propeller shaft 4, by the fore and aft motion of whichthe blades of the variable pitch propeller 5, are caused to take up thedesired pitch. Also shown is a locking piston 10, fed with oil or greaseby oil passages 9, through non-return valve 8, from manually operableauxiliary oil pump 11 with handle 12.

Referring now to FIGURE 2, hydraulic main piston 1,

in cylinder 2, is operated by oil pressure through the oil passages 14,and 15, from an oil pump (not shown) and a telernotor control valve (notshown) of well known construction. The locking piston or ram, 10, isfitted with sealing rings 13, the emergency oil or grease under highpressure being supplied from pump via non-return valve 8, and passagesto the cylinder 16, machined out of the solid intermediate propellershaft 4.

The description relating to the preferred embodiment and to FIGURES 1and 2 pre-supposes that the main piston moves toward the propeller inorder to move the blades to ahead pitch. In certain cases it may bedesirable for the operating piston to move away from the propeller toachieve ahead pitch and in suchcases the emergency ram will be in theform of an annular piston surrounding the operating rod aft of the mainpiston, or surrounding an extension of the operating rod forward of themain piston.

It is to be understood that the above description is by Way of exampleonly and that details for carrying the invention into effect may bevaried without departing from the scope of the invention claimed.

I claim:

1.- In a marine propulsion installation of the type embodying a variablepitch propeller, a propeller shaft, means operably coupled with saidpropeller for varying the pitch of said propeller, means defining a maincylinder Within said propeller shaft, a piston within said cylinderopen-ably connected to said operably coupled means, means forintroducing pressure fluid into said cylinder to displace said piston inthe desired direction for varying the pitch of the propeller, and-meansfor the auxiliary activation of the operably coupled means, such meansincluding means defining a further cylinder within said propeller shaftlocated centrally of and in communication with said main cylinder, ahigh pressure ram within said further cylinder, means for introducingpressure fluid into said further cylinder at a pressure sufficient tomove said ram into engagement with said piston and force said piston todisplace said operably coupled means whereby said propeller assumes theahead position, and non-return valve means associated with the means forintroducing fluid into the further cylinder for maintaining thepropeller in said last named position.

2. In a marine propulsion installation embodying a variable pitchpropeller, a propeller shaft adapted to be driven by a source of powerfor rotating said propeller, means defining a main cylinder within thepropeller shaft, a piston within the cylinder, a pull-push roddisplaceably mounted within the propeller shaft operably connected withsaid propeller and piston respectively for varying the pitch of saidpropeller, means for introducing pressure fluid into said cylinder todisplace said piston and pullpush rod in the desired direction forvarying the pitch of the propeller, and means for the auxiliaryactuation of the pull-push rod, such means including means defining afurther cylinder Within said propeller shaft located centrally of and incommunication with said main cylinder, a high pressure ram within saidfurther cylinder, means for introducing pressure fluid into said furthercylinder at a pressure suflicient to move said ram into engagement withsaid piston and displace said piston and pull-push rod to cause saidpropeller to assume the ahead position, and non-return valve meansassociated with the means for introducing fluid into the furthercylinder for maintaining the propeller in said last named position.

3. The marine propulsion installation as claimed in claim 2, in whichsaid means for introducing fluid into said further cylinder includes anaxial passage in the propeller shaft communicating with such cylinder, aradial passage leading from the axial passage to the outside of saidpropeller shaft, said non-return valve being located in said radialpassage, and means connecting said non-return valve to a source ofpressure fluid when said propeller shaft is stationary.

